wasi-libc/tools/wasi-headers/src/c_header.rs

613 lines
18 KiB
Rust

use heck::ShoutySnakeCase;
use witx::*;
pub fn to_c_header(doc: &Document, inputs_str: &str) -> String {
let mut ret = String::new();
ret.push_str(&format!(
r#"/**
* THIS FILE IS AUTO-GENERATED from the following files:
* {}
*
* @file
* This file describes the [WASI] interface, consisting of functions, types,
* and defined values (macros).
*
* The interface described here is greatly inspired by [CloudABI]'s clean,
* thoughtfully-designed, capability-oriented, POSIX-style API.
*
* [CloudABI]: https://github.com/NuxiNL/cloudlibc
* [WASI]: https://github.com/WebAssembly/WASI/
*/
#ifndef __wasi_api_h
#define __wasi_api_h
#ifndef __wasi__
#error <wasi/api.h> is only supported on WASI platforms.
#endif
#ifndef __wasm32__
#error <wasi/api.h> only supports wasm32; doesn't yet support wasm64
#endif
#include <stddef.h>
#include <stdint.h>
_Static_assert(_Alignof(int8_t) == 1, "non-wasi data layout");
_Static_assert(_Alignof(uint8_t) == 1, "non-wasi data layout");
_Static_assert(_Alignof(int16_t) == 2, "non-wasi data layout");
_Static_assert(_Alignof(uint16_t) == 2, "non-wasi data layout");
_Static_assert(_Alignof(int32_t) == 4, "non-wasi data layout");
_Static_assert(_Alignof(uint32_t) == 4, "non-wasi data layout");
_Static_assert(_Alignof(int64_t) == 8, "non-wasi data layout");
_Static_assert(_Alignof(uint64_t) == 8, "non-wasi data layout");
_Static_assert(_Alignof(void*) == 4, "non-wasi data layout");
#ifdef __cplusplus
extern "C" {{
#endif
// TODO: Encoding this in witx.
#define __WASI_DIRCOOKIE_START (UINT64_C(0))
"#,
inputs_str,
));
for nt in doc.typenames() {
print_datatype(&mut ret, &*nt);
}
for m in doc.modules() {
print_module(&mut ret, &m);
}
ret.push_str(
r#"#ifdef __cplusplus
}
#endif
#endif
"#,
);
ret
}
fn print_datatype(ret: &mut String, nt: &NamedType) {
if !nt.docs.is_empty() {
ret.push_str("/**\n");
for line in nt.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
match &nt.tref {
TypeRef::Value(v) => match &**v {
Type::Enum(e) => print_enum(ret, &nt.name, e),
Type::Int(i) => print_int(ret, &nt.name, i),
Type::Flags(f) => print_flags(ret, &nt.name, f),
Type::Struct(s) => print_struct(ret, &nt.name, s),
Type::Union(u) => print_union(ret, &nt.name, u),
Type::Handle(h) => print_handle(ret, &nt.name, h),
Type::Builtin { .. }
| Type::Array { .. }
| Type::Pointer { .. }
| Type::ConstPointer { .. } => print_alias(ret, &nt.name, &nt.tref),
},
TypeRef::Name(_) => print_alias(ret, &nt.name, &nt.tref),
}
}
fn print_alias(ret: &mut String, name: &Id, dest: &TypeRef) {
match &*dest.type_() {
Type::Array(_) => {
// Don't emit arrays as top-level types; instead we special-case
// them in places like parameter lists so that we can pass them
// as pointer and length pairs.
}
_ => {
if name.as_str() == "size" {
// Special-case "size" as "__SIZE_TYPE__" -- TODO: Encode this in witx.
ret.push_str(&format!(
"typedef __SIZE_TYPE__ __wasi_{}_t;\n",
ident_name(name)
));
} else {
ret.push_str(&format!(
"typedef {} __wasi_{}_t;\n",
typeref_name(dest),
ident_name(name)
));
}
ret.push_str("\n");
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
dest.mem_size_align().size
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
dest.mem_size_align().align
));
ret.push_str("\n");
}
}
}
fn print_enum(ret: &mut String, name: &Id, e: &EnumDatatype) {
ret.push_str(&format!(
"typedef {} __wasi_{}_t;\n",
intrepr_name(e.repr),
ident_name(name)
));
ret.push_str("\n");
for (index, variant) in e.variants.iter().enumerate() {
if !variant.docs.is_empty() {
ret.push_str("/**\n");
for line in variant.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
"#define __WASI_{}_{} ({}({}))\n",
ident_name(&name).to_shouty_snake_case(),
ident_name(&variant.name).to_shouty_snake_case(),
intrepr_const(e.repr),
index
));
ret.push_str("\n");
}
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
e.repr.mem_size()
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
e.repr.mem_align()
));
ret.push_str("\n");
}
fn print_int(ret: &mut String, name: &Id, i: &IntDatatype) {
ret.push_str(&format!(
"typedef {} __wasi_{}_t;\n",
intrepr_name(i.repr),
ident_name(name)
));
ret.push_str("\n");
for (index, const_) in i.consts.iter().enumerate() {
if !const_.docs.is_empty() {
ret.push_str("/**\n");
for line in const_.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
"#define __WASI_{}_{} ({}({}))\n",
ident_name(&name).to_shouty_snake_case(),
ident_name(&const_.name).to_shouty_snake_case(),
intrepr_const(i.repr),
index
));
ret.push_str("\n");
}
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
i.repr.mem_size()
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
i.repr.mem_align()
));
ret.push_str("\n");
}
fn print_flags(ret: &mut String, name: &Id, f: &FlagsDatatype) {
ret.push_str(&format!(
"typedef {} __wasi_{}_t;\n",
intrepr_name(f.repr),
ident_name(name)
));
ret.push_str("\n");
for (index, flag) in f.flags.iter().enumerate() {
if !flag.docs.is_empty() {
ret.push_str("/**\n");
for line in flag.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
"#define __WASI_{}_{} ({}({}))\n",
ident_name(name).to_shouty_snake_case(),
ident_name(&flag.name).to_shouty_snake_case(),
intrepr_const(f.repr),
1u128 << index
));
ret.push_str("\n");
}
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
f.repr.mem_size(),
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
f.repr.mem_align(),
));
ret.push_str("\n");
}
fn print_struct(ret: &mut String, name: &Id, s: &StructDatatype) {
ret.push_str(&format!(
"typedef struct __wasi_{}_t {{\n",
ident_name(name)
));
for member in &s.members {
if !member.docs.is_empty() {
ret.push_str(" /**\n");
for line in member.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
" {} {};\n",
typeref_name(&member.tref),
ident_name(&member.name)
));
ret.push_str("\n");
}
ret.push_str(&format!("}} __wasi_{}_t;\n", ident_name(name)));
ret.push_str("\n");
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
s.mem_size()
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
s.mem_align()
));
for layout in s.member_layout() {
ret.push_str(&format!(
"_Static_assert(offsetof(__wasi_{}_t, {}) == {}, \"witx calculated offset\");\n",
ident_name(name),
ident_name(&layout.member.name),
layout.offset
));
}
ret.push_str("\n");
}
fn print_union(ret: &mut String, name: &Id, u: &UnionDatatype) {
ret.push_str(&format!(
"typedef union __wasi_{}_u_t {{\n",
ident_name(name)
));
for variant in &u.variants {
if let Some(ref tref) = variant.tref {
if !variant.docs.is_empty() {
ret.push_str(" /**\n");
for line in variant.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
" {} {};\n",
typeref_name(tref),
ident_name(&variant.name)
));
}
}
ret.push_str(&format!("}} __wasi_{}_u_t;\n", ident_name(name)));
ret.push_str(&format!(
"typedef struct __wasi_{}_t {{\n",
ident_name(name)
));
ret.push_str(&format!(" {} tag;\n", namedtype_name(&u.tag)));
ret.push_str(&format!(" __wasi_{}_u_t u;\n", ident_name(name)));
ret.push_str(&format!("}} __wasi_{}_t;\n", ident_name(name)));
ret.push_str("\n");
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
u.mem_size()
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
u.mem_align()
));
let l = u.union_layout();
ret.push_str(&format!(
"_Static_assert(offsetof(__wasi_{}_t, u) == {}, \"witx calculated union offset\");\n",
ident_name(name),
l.contents_offset,
));
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_u_t) == {}, \"witx calculated union size\");\n",
ident_name(name),
l.contents_size,
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_u_t) == {}, \"witx calculated union align\");\n",
ident_name(name),
l.contents_align,
));
ret.push_str("\n");
}
fn print_handle(ret: &mut String, name: &Id, h: &HandleDatatype) {
ret.push_str(&format!("typedef int __wasi_{}_t;", ident_name(name)));
ret.push_str(&format!(
"_Static_assert(sizeof(__wasi_{}_t) == {}, \"witx calculated size\");\n",
ident_name(name),
h.mem_size()
));
ret.push_str(&format!(
"_Static_assert(_Alignof(__wasi_{}_t) == {}, \"witx calculated align\");\n",
ident_name(name),
h.mem_align()
));
ret.push_str("\n");
}
fn print_module(ret: &mut String, m: &Module) {
ret.push_str("/**\n");
ret.push_str(&format!(" * @defgroup {}\n", ident_name(&m.name),));
for line in m.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" * @{\n");
ret.push_str(" */\n");
ret.push_str("\n");
for func in m.funcs() {
print_func(ret, &func, &m.name);
}
ret.push_str("/** @} */\n");
ret.push_str("\n");
}
fn print_func(ret: &mut String, func: &InterfaceFunc, module_name: &Id) {
if !func.docs.is_empty() {
ret.push_str("/**\n");
for line in func.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
if !func.results.is_empty() {
let first_result = &func.results[0];
if !first_result.docs.is_empty() {
ret.push_str(" * @return\n");
for line in first_result.docs.lines() {
ret.push_str(&format!(" * {}", line));
}
}
}
ret.push_str(" */\n");
}
if func.results.is_empty() {
// Special-case "proc_exit" as _Noreturn -- TODO: Encode this in witx.
if func.name.as_str() == "proc_exit" {
ret.push_str("_Noreturn ");
}
ret.push_str("void ");
} else {
let first_result = &func.results[0];
ret.push_str(&format!("{} ", typeref_name(&first_result.tref)));
}
ret.push_str(&format!("__wasi_{}(\n", ident_name(&func.name)));
if func.params.is_empty() && func.results.len() <= 1 {
ret.push_str(" void\n");
}
for (index, param) in func.params.iter().enumerate() {
if !param.docs.is_empty() {
ret.push_str(" /**\n");
for line in param.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
add_params(ret, &ident_name(&param.name), &param.tref);
ret.push_str(&format!(
"{}\n",
if index + 1 < func.params.len() || func.results.len() > 1 {
",\n"
} else {
""
}
));
}
for (index, result) in func.results.iter().enumerate() {
if index == 0 {
// The first result is returned by value above.
continue;
}
if !result.docs.is_empty() {
ret.push_str(" /**\n");
for line in result.docs.lines() {
ret.push_str(&format!(" * {}\n", line));
}
ret.push_str(" */\n");
}
ret.push_str(&format!(
" {} *{}{}\n",
typeref_name(&result.tref),
ident_name(&result.name),
if index + 1 < func.results.len() {
","
} else {
""
}
));
}
ret.push_str(") __attribute__((\n");
ret.push_str(&format!(
" __import_module__(\"{}\"),\n",
ident_name(module_name)
));
ret.push_str(&format!(
" __import_name__(\"{}\")",
ident_name(&func.name)
));
if !func.results.is_empty() {
ret.push_str(",\n __warn_unused_result__\n");
}
ret.push_str("));\n");
ret.push_str("\n");
}
fn add_params(ret: &mut String, name: &str, tref: &TypeRef) {
match &*tref.type_() {
Type::Builtin(BuiltinType::String) => {
ret.push_str(&format!(" const char *{},\n", name));
ret.push_str("\n");
ret.push_str(" /**\n");
ret.push_str(&format!(
" * The length of the buffer pointed to by `{}`.\n",
name,
));
ret.push_str(" */\n");
ret.push_str(&format!(" size_t {}_len", name));
}
Type::Array(element) => {
ret.push_str(&format!(
" const {} *{},\n",
typeref_name(&element),
name
));
ret.push_str("\n");
ret.push_str(" /**\n");
ret.push_str(&format!(
" * The length of the array pointed to by `{}`.\n",
name,
));
ret.push_str(" */\n");
ret.push_str(&format!(" size_t {}_len", name));
}
_ => {
ret.push_str(&format!(" {} {}", typeref_name(tref), name));
}
}
}
fn ident_name(i: &Id) -> String {
i.as_str().to_string()
}
fn builtin_type_name(b: BuiltinType) -> &'static str {
match b {
BuiltinType::String | BuiltinType::Char8 => {
panic!("no type name for string or char8 builtins")
}
BuiltinType::USize => "size_t",
BuiltinType::U8 => "uint8_t",
BuiltinType::U16 => "uint16_t",
BuiltinType::U32 => "uint32_t",
BuiltinType::U64 => "uint64_t",
BuiltinType::S8 => "int8_t",
BuiltinType::S16 => "int16_t",
BuiltinType::S32 => "int32_t",
BuiltinType::S64 => "int64_t",
BuiltinType::F32 => "float",
BuiltinType::F64 => "double",
}
}
fn typeref_name(tref: &TypeRef) -> String {
match &*tref.type_() {
Type::Builtin(BuiltinType::String) | Type::Builtin(BuiltinType::Char8) | Type::Array(_) => {
panic!("unsupported grammar: cannot construct name of string or array",)
}
_ => {}
}
match tref {
TypeRef::Name(named_type) => namedtype_name(&named_type),
TypeRef::Value(anon_type) => match &**anon_type {
Type::Array(_) => unreachable!("arrays excluded above"),
Type::Builtin(b) => builtin_type_name(*b).to_string(),
Type::Pointer(p) => format!("{} *", typeref_name(&*p)),
Type::ConstPointer(p) => format!("const {} *", typeref_name(&*p)),
Type::Int(i) => format!("{}", intrepr_name(i.repr)),
Type::Struct { .. }
| Type::Union { .. }
| Type::Enum { .. }
| Type::Flags { .. }
| Type::Handle { .. } => unreachable!(
"wasi should not have anonymous structs, unions, enums, flags, handles"
),
},
}
}
fn namedtype_name(named_type: &NamedType) -> String {
match &*named_type.type_() {
Type::Pointer(p) => format!("{} *", typeref_name(&*p)),
Type::ConstPointer(p) => format!("const {} *", typeref_name(&*p)),
Type::Array(_) => unreachable!("arrays excluded above"),
_ => format!("__wasi_{}_t", named_type.name.as_str()),
}
}
fn intrepr_name(i: IntRepr) -> &'static str {
match i {
IntRepr::U8 => "uint8_t",
IntRepr::U16 => "uint16_t",
IntRepr::U32 => "uint32_t",
IntRepr::U64 => "uint64_t",
}
}
fn intrepr_const(i: IntRepr) -> &'static str {
match i {
IntRepr::U8 => "UINT8_C",
IntRepr::U16 => "UINT16_C",
IntRepr::U32 => "UINT32_C",
IntRepr::U64 => "UINT64_C",
}
}